I don't think you should stress yourself out over what terms are canon or not. Final Fantasy as a whole has a long history of flip-flopping with terminology, and sometimes lampshades it. A prime example being the Summons, or are they Eidolons? Espers? Aeons? How about the volcano in FF1. Is it Gulg, Gulug, or Gurgu? The Crystal Tower in FF3? A Realm Reborn calls it the Syrcus Tower. The list goes on, from locations to items. A similar thing happened with Dragon Quest, but that was mostly because a go-to master list of English terminology wasn't written until DQ8. Here, it almost feels deliberate, somewhat. So, if anything, maybe make the "canon terminology" consistent with other PS1 FFs.